TM 1-1500-204-23-9Figure 3-44. Reading a Metric Micrometer(3) Thimble graduations. The thimble (3) isgraduated in 50 divisions with every fifth line beingnumbered. Each line represents a distance of 1/100, or0.01 mm.(4) Reading a measurement. A measurementcan be read as follows:Read the highest whole number visible on thebarrel (5) and record ................. 20 = 20.0 mmCount the number of lines visible between the20 and the thimble edge (4) and record 2 = 2.0 mmLocate the line on the thimble (3) that coincideswith or has passed the horizontal line in thebarrel (2) and record ..... 36 = 36/100 = 0.36 mmTotal all preceding measurements ..... 22.36 mmThe measurement, therefore, is 22.36 millimeters.g. TransferringMeasurementsfromInsideCaliperorInsideMicrometertoMicrometerCaliper.When itbecomes necessary to transfer a measurement from aninside caliper to an outside caliper, perform the followingprocedures: TM 1-1500-204-23-9(1) After setting inside caliper or insidemicrometer to the work, hold the micrometer caliper inone hand and the inside tool in the other hand.(2) Turn the thimble of the micrometer caliperwith the thumb and forefinger until the inside tool legslightly contact the anvil and spindle of the micrometercaliper.(3) Hold the tips of the inside tool legs parallelto the axis of the micrometer caliper spindle.(4) The micrometer caliper will be accuratelyset when the inside tool will just pass between the anviland spindle by its own weight.h. MicrometerAdjustmentandTesting.At times itmay become necessary to adjust and/or test theaccuracy of a micrometer.(1) Adjustment.Micrometer may be adjusted tocompensate for thread wear. Adjust as follows.(a) Unscrew thimble from barrel.(b) Tighten the thread play adjustment nuton the fixed nut a fraction of a turn at a time.(c) Test the fit of the micrometer screw inthe fixed nut.(d) Repeat the tightening and test in thefixed nut until the operation is free from binding andplay.(2) Testing. A micrometer is tested foraccuracy as follows:(a) Clean the measuring faces with a softcloth and examine the faces for any lint left by the cloth.(b) Measure the length of the micrometertest gauge of the same length as the minimum capacityof the micrometer.(c) The micrometer should read the exactmeasurement.(d) For the 1-inch micrometer, screw thethimble down until the spindle contacts the anvil. Thereading should be 0.000 inch.3-19